P0304 coded Duramax 2006 LBZ

2006 Duramax throwing a P0304 code.
I have rebuilt injectors freshly installed so I know they are good.
I've used a test light on the injector plug and it is pulsing.
I've checked the injector pulse wire from the injector back to the unplugged computer box and there are no shorts.
It has a rough idle with whitish grey looking exhaust until I punch it after it warms up then it's dark grey almost black.
If I unplug the injector it still smokes the same which I would think it shouldn't if it's not getting fuel.

It started running bad one night and even felt like the steering box had came off the frame it felt so rough in my hand.
It was missing real bad and smelled like raw fuel when I got out to check.

I got the 304 code and threw a set of rebuilt injectors in it since it was 14 years old.
I've been 3 months trying to get it to run right and not throw the 304 , I'm broke and half out of my mind !

HELP before they have me committed to the padded room hotel ...

Is coolant level low? Whitish smoke can be egr cooler leaking or turbo leaking oil internally (check for oil sludge inside intercooler tubes). Do you have a ocilliscope? Check injector waveform if you do have one. Whats your fuel pressures hi and low side? And oil pressures?

I'll reserve you a room ....

Coolant was good when this occurred but is low now even though I put water in the reservoir , it's not sucked it out. Whitish smoke is at start up and until engine temp gets to 180 then it gets darker toward grey.

There's not "sludge" in intercooler tube but there is an oil film.

I do have an old BK scope but I probably couldn't figure it out , although I used to use it to check power mic boards I use to make but that was 30+ years ago. I've forgot more than I ever knew since then !

Fuel pressure ... ? No gauge.
Low side has a brand new 165psi AirDog as the old one died sometime during this fiasco.

Oil pressure has always idled 30psi since I first changed oil. I've only had the truck 15 months on the road (+ 3 broke down).
Oil pressure driving is toward 60psi.

I'm almost leaning toward hole in the piston , maybe from glow plug tip.
I checked the oil and I can't tell if it's gaining or not with the stupid spiral stick. I can't tell where the oil level ends. It doesn't feel thinned out though.

Oil film is how it starts for turbo bearing wearing out. How much oil does it use in between oil changes? Also your injectors may use oil to open/close while operating so i would reccomend ya dust them brain files off for your scope and see whats going on with the injector waveform and also check with a scanner what your injector oil pressure readings are as a injector tube loosing its seal can leak/spray oil into cylinder preventing a complete burn of the fuel.

The other thing to check is glow plug remove it from the hole and see if it glows orange or red. It should glow orange to bright orange and should heat up almost instantly.

What would a glow plug have to do with it running after it's started ?

A weak glowplug can cause a perlonged warm up of one cylinder and possibly excessive carbon build up in a cylinder preventing a proper burn. Just depends on the circumstances 9 out of 10 times it will make it idle rough on startup and after a bit work fine. but if injector or injector tube fails it can possibly cause a dead cylinder or puff black smoke aka a heavy soot.

I've got new GPs but didn't put them in. I had such a hard time getting the old injectors out I figured my luck would break a plug or two.
Two of us were 2 days getting one injector out. I think I can add 3 more bad disc to my already 6 shot disc. I almost ripped the engine out by the roots pulling on that one.
I could maybe change them tomorrow but I'd hate myself for it.

To me a "misfire" means no squirt from the injector or a hole in the piston.
I've thought about pulling the injector and putting my camera through the hole to look at the piston top.

Well it would be easier to put the cam in there now. just remember to pull the fuel pump and injector fuses jf your doing that to check the plug.